Maximising product lifetime

Poorly designed PSU's can get VERY hot. This Is really a function of the power specification and the inefficiency of the product design. However, is this really important?

Considering market trends to move away from disposability, this necessitates migration to products with a longer lifetime.

We have recently worked with a customer on the design of a product for 7 year lifetime in continuous full-load operation = 61320 hours. A key factor in the lifetime of a power supply is the performance of the electrolytic capacitors used in the design.

The Arrhenius equation applied to the capacitors show that the component lifetime is based on the applied voltage vs the voltage ratings, but the more important term is an exponential change in a lifetime based on the operating temperature of the component vs the temperature ratings.

By careful selection of high-quality Japanese capacitors used in a high-efficiency design, we were able to limit the capacitor temperature to exceed the customer lifetime requirements.